When required by the commission, the application for a certification document or the renewal thereof shall be accompanied by a certificate in such form as shall be prescribed by the commission, from a physician and surgeon licensed under the provisions of the Business and Professions Code or a physician assistant practicing in compliance with Chapter 7.7 (commencing with Section 3500) of Division 2 of the Business and Professions Code, showing that the applicant is free from any contagious and communicable disease or other disabling disease or defect unfitting the applicant to instruct or associate with children.